Ako Udagawa is a student at Haneoka Girls' Academy and the drummer for the band Roselia. Standing 148 centimeters tall, she is the shortest member of Roselia. She has long, naturally curly light purple hair styled into curled pigtails with straightened bangs, sharp crimson eyes, and is often depicted with a fanged tooth. Her casual fashion blends punk and gothic elements with a cute flair. Ako exhibits pronounced chuunibyou tendencies, often indulging in grandiose delusions and references to magical powers, a trait her best friend Rinko Shirokane links to her frequent online gaming. Despite these fantasies, she remains cheerful, energetic, and sociable, though her dramatic speech sometimes falters due to limited vocabulary. Within Roselia, she is treated as a younger sister figure because of her childlike demeanor. Her hobbies include seeking out cool trends, playing Neo Fantasy Online (where she mains the Necromancer class), enjoying horror stories, haunted houses, and fireworks. She dislikes eggs, peppers, and sea cucumber, while favoring potato chips and jelly beans. Ako is also a skilled swimmer. She deeply admires her older sister Tomoe Udagawa, who inspired her to take up drumming. She idolizes her bandmate Yukina Minato and shares her closest bond with Rinko, whom she calls Rin-rin and met through Neo Fantasy Online. Initially insecure about her drumming abilities and struggling with reading sheet music, Ako gradually gains confidence through dedication, and her bandmates come to accept her unique traits. Her birthday is July 3.